Asymmetries in {\bar B}_d^0 -> {\bar K}^{*0} e+ e- decay and contribution of vector resonances

TL;DR

This paper analyzes the angular distribution and asymmetries in the rare decay {ar B}_d^0 -> {ar K}^{*0} e+ e-, emphasizing the impact of vector resonances and comparing different models to improve understanding of this flavor-changing neutral current process.

Contribution

It introduces a detailed treatment of vector resonance contributions in the decay and compares models, enhancing the accuracy of theoretical predictions for observables.

Findings

Calculated invariant mass dependence of branching ratio and asymmetries.

Compared model predictions with Belle and CDF data.

Provided predictions for LHCb experiments.

Abstract

The fully differential angular distribution for the rare flavor-changing neutral current decay {\bar B}_d^0 -> {\bar K}^{*0} (-> K^- \pi^+) e+ e- is studied. The emphasis is placed on accurate treatment of the contribution from the processes \bar{B}_d^0 -> \bar{K}^{*0} (-> K^- pi^+) V with intermediate vector resonances V = \rho(770), \omega(782), \phi(1020), J/\psi, \psi(2S), ... decaying into the e+ e- pair. The two versions of the vector-meson-dominance model for the transition V \gamma are used and tested. The present method of including vector resonances is also compared with the existing in the literature method. The electron-positron invariant mass dependence of the branching ratio and various asymmetries is calculated. The branching ratio, longitudinal polarization fraction of the {\bar K}^{*0} meson, transverse asymmetry A_T^{(2)} and forward-backward asymmetry are compared with data from Belle and CDF, and predictions for experiments at LHCb are made.